PMID- 10653665
OWN - NLM
STAT- MEDLINE
DCOM- 20000229
LR  - 20190613
IS  - 0006-2960 (Print)
IS  - 0006-2960 (Linking)
VI  - 39
IP  - 5
DP  - 2000 Feb 8
TI  - Phosphorylation of recombinant human ATP:citrate lyase by cAMP-dependent protein 
      kinase abolishes homotropic allosteric regulation of the enzyme by citrate and
      increases the enzyme activity. Allosteric activation of ATP:citrate lyase by
      phosphorylated sugars.
PG  - 1169-79
AB  - Recombinantly expressed human ATP:citrate lyase was purified from E. coli, and
      its kinetic behavior was characterized before and after phosphorylation. Cyclic
      AMP-dependent protein kinase catalyzed the incorporation of only 1 mol of
      phosphate per mole of enzyme homotetramer, and glycogen synthase kinase-3
      incorporated an additional 2 mol of phosphate into the phosphorylated protein.
      Isoelectric focusing revealed that all of the phosphates were incorporated into
      only one of the four enzyme subunits. Phosphorylation resulted in a 6-fold
      increase in V(max) and the conversion of citrate dependence from sigmoidal,
      displaying negative cooperativity, to hyperbolic. The phosphorylated recombinant 
      enzyme is more similar to the enzyme isolated from mammalian tissues than
      unphosphorylated enzyme with respect to the K(m) for citrate, CoA, and ATP, and
      the specific activity. Fructose 6-phosphate was found to be a potent activator
      (60-fold) of the unphosphorylated recombinant enzyme, with half-maximal
      activation at 0.16 mM, which results in a decrease in the apparent K(m) for
      citrate and ATP, as well as an increase in the V(max) of the reaction. Thus,
      human ATP:citrate lyase activity is regulated in vitro allosterically by
      phosphorylated sugars as well as covalently by phosphorylation.
FAU - Potapova, I A
AU  - Potapova IA
AD  - Department of Physiology and Biophysics, School of Medicine, State University of 
      New York at Stony Brook, Stony Brook, New York 11794-8661, USA.
FAU - El-Maghrabi, M R
AU  - El-Maghrabi MR
FAU - Doronin, S V
AU  - Doronin SV
FAU - Benjamin, W B
AU  - Benjamin WB
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Recombinant Proteins)
RN  - 0 (Sugar Phosphates)
RN  - 2968PHW8QP (Citric Acid)
RN  - EC 2.3.3.8 (ATP Citrate (pro-S)-Lyase)
RN  - EC 2.7.11.11 (Cyclic AMP-Dependent Protein Kinases)
SB  - IM
MH  - ATP Citrate (pro-S)-Lyase/biosynthesis/genetics/isolation &
      purification/*metabolism
MH  - Allosteric Regulation
MH  - Animals
MH  - Catalysis
MH  - Citric Acid/chemistry/*metabolism
MH  - Cyclic AMP-Dependent Protein Kinases/*physiology
MH  - Enzyme Activation
MH  - Humans
MH  - Kinetics
MH  - Phosphorylation
MH  - Plasmids/metabolism
MH  - Rats
MH  - Recombinant Proteins/biosynthesis/isolation & purification/*metabolism
MH  - Substrate Specificity
MH  - Sugar Phosphates/chemistry/metabolism/*physiology
EDAT- 2000/02/02 09:00
MHDA- 2000/03/04 09:00
CRDT- 2000/02/02 09:00
PHST- 2000/02/02 09:00 [pubmed]
PHST- 2000/03/04 09:00 [medline]
PHST- 2000/02/02 09:00 [entrez]
AID - bi992159y [pii]
AID - 10.1021/bi992159y [doi]
PST - ppublish
SO  - Biochemistry. 2000 Feb 8;39(5):1169-79. doi: 10.1021/bi992159y.